Ergonomic design (also known as human factors, comfort design or functional design) is the practice of designing products, systems, or processes to take proper account the interaction with people (users), and may include disciplines, such as psychology, engineering, biomechanics, industrial design, physiology, etc. Ergonomics includes design of equipment and devices that fit with usage of the human body. The International Ergonomics Association defines ergonomics or human factors as the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance.